Abstract: In order to investigate the effect of protein oxidation during storage on the cooking and eating quality of rice, newly harvested ‘Jinyou 207’ indicia rice and ‘Jijing 88’ japonica rice were stored under accelerated deterioration conditions (37 ℃ and 85% relative humidity). The results indicated that the degree of protein oxidation was increased with increasing storage time of rice. The peak viscosity, final viscosity and setback of rice flour and cooked rice hardness were significantly correlated positively with the protein carbonyl content in rice and negatively with the total sulphydryl content and free sulphydryl content (P < 0.01). Cooked rice chewiness, springiness, appearance, smell, palatability, taste and cold cooked rice texture were negatively correlated with the protein carbonyl content of rice (P < 0.01), and positively correlated with the total sulphydryl content and free sulphydryl content (P < 0.01). The disulfide content of rice protein was significantly positively correlated with rice flour minimum viscosity and cooked rice hardness and negatively correlated with the cohesiveness, resilience and adhesiveness of cooked rice (P < 0.01). In conclusion, our data demonstrated that during accelerated storage, the degree of retrogradation of rice starch increased with increasing degree of protein oxidation, and the texture properties and sensory quality of cooked rice decreased obviously.

Key words: rice, storage, protein oxidation, pasting properties, texture properties, sensory qualities